Method and apparatus for electrolytic coating of strip material



KLEIN METHOD AND APPARATUS FOR ELECTROLYTIC COATING 0F STRIP MATERIAL 3 Sheets-Sheet 1 Filed Feb. 24, 1944 INVENTOR Clarence d K/e/n C. J. KLEIN METHOD AND APPARATUS FOR ELECTROLYTIC COATING 0F STRIP MATERIAL 3 Sheets-Sheet 2 Filed Feb. 24, 1.944

QM. mvfimb rmtmlwgtmfin GE E E E EmE EwE E kwfiw pm A EN A Wm May 30, 1950 c. J. KLEIN METHOD AND APPARATUS FOR ELECTROLYTIC COATING OF STRIP MATERIAL 5 Sheets-Sheet 5 Filed Feb. 24, 1944 INVENTOR I C/awence (j file/n Patented May 30, 1950 METHOD AND APPARATUS. FOR ELECTROe LYTIC COATING OF STRIP MATERIAL Clarence J. Klein; Hollidays Cove, W. Vat, as-

signer to National'Steel Corporation; acorpo ration oi Delaware Application February 24, 1944, Serial No. 523,681

6 Claims. ill. 204-28) jected to numerous stages ofeleotrodeposi'tion in l the several pans whereby a continuous coating of metal is eventually deposited onto the strip from anodesdisposed in the pans. The number of pans required is considerable because it is convenient to coat one side only of the strip ata time, the preferred arrangement comprising two vertically spaced tiers of pans, one tier servingto coat one side and the other tier the other side, after the strip has been turned over; The delivery of electrolyte to such a large number of pans by means of pumps and supply and returnpipe connections between them to the individual pans, presents a serious problem because of the complexity of the piping which would" be necessary and thedifiiculty of accommodating numerous pipelines inflthe available space.

I have invented a novel method and" apparatus for coating strip whereby the supply of electrolyte to the several pans is greatly simplified, without impairing the effectiveness of the electroplating operation performed in each pan. In a preferred embodiment and practice of the. invention, I mount the several electrolyte pans at progressively different elevations and provide suitable connections between adjacent pans to permit gravity flowof electrolyte from each pan tothe adjacent; nextloWeripaI -w By this arrangement, electrolyteis initially delivered to, the highest pan and flows; therefrom downwardly through the remaining pans. Sufiicient circulation of electrolyte ismaintainecl; to fill the several pans and; permit an overflow of electrolyte therefrom intoa collectingtank from which: it may again be returned to the: highest pan. In order to maintainthestrip at the proper elevation relative to the surface of the electrolyte inthe several pans and atthetproperj distance from theanode in each pan, Lprovidemeansinthejform oivvpairs of rollsbetween adjacent. pans for changing the elevationof thestrip. by the same amount as the diiference between the elevations of adjacent pans." These rolls may convenientlybethe eonr tactrolls by whichlelectric current is supplieduto the strip for electrodeposition.

The novel features and advantages of the invention may be cl'early'understoodfrom the following detailed description which refers" to the accompanying drawings illustrating the preferred embodiment and practice. In the drawings,

Figures IA, 113 and lCni'sposedsi'de by side constitute a diagrammatic side elevation of an elec= trolytic coating line embodying my inventiorn" Figure 2 is a partial longitudinal section through several" electrolyte pans; with parts in elevation;

Figure 3 is a transverse section taken along the plane oili'ne IIIIII of'Figure 2; and

Figure 4 is a verticalsectib'rr through the rolls adjacent one of the, housings therefor which is shown in elevation.

Referring in detaiI to the drawings, at the head of the coatingnline are provided" uncoil'ers iii and ll to whichcoils of strip are delivered from a conveyor l2',wacrop shear iiihavihgpihch rolls, a seam Welder i l and delivery pinch rolls It. A looping pit Ill accommodates a sufficient length of materialttopermit continuous travel of the strip through the apparatus subsequently to be described,,whi1e allowing for the stoppage of the trailing end of a coil so itcan be sheared and welded to theusucceeding coil. From the looping pit the strip. passes through a drag unit ll and into anaelectrolytic cleaning tankl8 having deflector rollsul9 therein. In the tank It the strip is subj ectedtto an initial electrolytic cleaning. Itnext passesthrzough ascrubbervilii which mechanically removes-mostlof the dirt and grease loosened the electrolysis :occurringjin the tank lit. The strip; nextmasses through a pickling tank Zlhaving deflector rolls iilwherein thematerial N is subjected tolapickling; to remove traces oflscale andpreparerthesurfacetonplatingu The strip then passes tin-ought atsecond lscrubber 23 which removes anys solution remaining: thereon from itswpassage-a througlrstanla 2i.v

l roint the scrubber: 2 3;, the": strip: passesi: under a deflectors rolll andktbetween'i the first ot a pluralityvoiapairs trolls zfirdisposedi at opposite ends-.ofla; numbel electrolyte-pans. Atplura-lity of pansciifia are disposed side bysidei'n a, lower tier: similait: pansu Zaii are disposedl sideeby side; intani uppentier: above theilowerr tier; Drip troughsz 28 areelocat'edthelow the rolls Zitand 5, collecting: tanln ZQsextends the fulldength: of; the two tiers; pans Zfilof thetlower. tier are disposed at progressively; lower; elevations; going from left to. rightg in e.,Mthe direetioni ofiztravel oft'he strip. The-strip issguidedlfroznztheilower tier. of pans: ZBxto; the upper: tieriby z-defiecton-rrolls 30. The pans 21 of the upper tier are positioned on progressively lower elevations going from right to left which is the direction in which the strip travels over these pans. It will be understood that first one side and then the other of the strip is subjected to repeated electroplating in passing over the pans of one of the tiers, the bottom surface of the strip being exposed to the electrolyte in both cases. Suitable electric connections extend from one roll of each pair 25 to a source of current and from the latter to anodes 3! (see Figures 2 and 3) disposed in the pans. As shown in the drawings, the anodes are supported on inclined guides 32 and 33. They are advanced progressively crosswise of the pans, the inclination of the guides serving to maintain substantially constant the spacing between the strip and the upper surfaces of the anodes as the latter are dissolved by the electroplating action. The anodes may be of tin if it is desired to coat the strip with that metal, or of zinc if a galvanizing treatment is to be effected.

From the upper tier of electrolyte pans, the strip passes over deflector rolls 34 and rolls 35 in a trough adapted to receive electrolyte dripping from the strip. It next passes under deflector rolls 35 in a rinse tank 37 and thence over rolls 38 above a drip pan 35. The strip then passes through a brushing apparatus iii, a hot rinse tank 4|, a dryer 42 and over tensioning rolls 43 into a looping pit 44. The strip is drawn from the pit through drag unit 45 and a cut-out shear 55 by recoilcrs W.

In order to provide for gravity flow of electrolyte from each pan to the next pan below, a pipe connection 48 extends between each pair of adjacent pans. Thus electrolyte supplied to the highest pan of the upper tier flows downwardly through the several pans 21 successively. A pipe connection may extend from the lowest pan 2? to the highest pan 25 so that the electrolyte, after flowing through all the pans 27, similarly traing members 55 extending across the coating line and are connected at their upper ends by a transom 56. The chucks 54 rest on springs 51. Adjusting screws 58 extend upwardly from the bottom of the frames 50 for supporting the springs. Screws 59 for adjusting the pressure of the rolls extend through the upper ends of the frames. It will be noted that the ways 5! and 53 are so disposed that the axes of the rolls 25 are displaced from each other horizontally. This relation of the rolls causes the strip to be deflected downwardly, as it passes from one tank to the next, as clearly as shown in Figure 2. The housings are designed so that the deflection of the strip from one pan to the next is substantially equal to the difference between the elevations of adjacent pans.

As previously indicated, the rolls 25 are utilized for making electrical connections to the strip. The upper roll 25 is preferably the contact roll, being composed of metal and having its surface in contact with the strip. The lower roll serves merely as a backing roll and preferably has its surface covered with rubber. A brush-holder frame til is secured to but insulated from each housing frame 56 and is provided with brush holders El, 62 and 63. The holders B2 and 63 are mounted on an upper cross member 64 of the brush holder which is pivoted to one of the side members so it may be swung upwardly to permit the upper roll to be changed as may be necessary. Brushes in the holders BI, 62 and 63 have sliding contact with the necks 65 of the upper roll 25. Bus bar connections 66 extend from the brush holder frames to the current verses the several pans 25. Suilicient circulation of electrolyte is maintained to cause the several pans to fill and overflow slightly. The overflow is collected in the tank 29. Instead of the electrolyte flowing through all of pans 21 and 26, pipe connections (not shown) may extend from intermediate points to tank 29. Electrolyte may be pumped from tank 25 to the highest pan 21 and, if desired, to intermediate points, by means of any suitable pump and pipe connections. Branch connections 59 may be provided in some of the connecting pipes 48, in order to control the circulation as desired, by delivering a supplemental flow of electrolyte therethrough. Valves 48 and 49' are provided to control the rate of flow through the pipes 48 and 49.

- As shown in Figure 2, the strip passing over each of the pans is maintained horizontal by the rolls 25 at opposite ends of the pan. In order to maintain the same position of the strip relative to the surface of the electrolyte and to the anodes in the several pans, I arrange the rolls 25 to deflect the strip downwardly as it passes from one pan to the next. The rolls 25 may be journaled in any suitable housings, such as that shown in Figure 4 The housing there illustrated comprises a frame having ways 5i for a chuck 52 in which the upper roll 25 is journaled. The frame also has ways 53 adapted to receive a chuck 54 in which the lower roll 25 1s journaled. It will be understood that a pair of housings is provided for supporting each pair of rolls 25. The housing frames rest on supportsource.

It will be apparent from the foregoing that my invention provides a highly advantageous method and apparatus for electrolytic coating in that the supply of electrolyte to the numerous pans is greatly simplified by the provisions for gravity flow through the pans successively. This arrangement of the pans does not introduce any additional complications into the apparatus and reduces to a minimum the number and complexity of the piping connections necessary to insure a suitable supply of electrolyte in each pan at all times. The arrangement of the rolls between pans which serve as guide rolls as well as contact rolls, insures that the strip is maintained in the same relation to the surface of the electrolyte in each pan so thata uniform plating effect will be accomplished as any point on the strip travels over each pan. The arrangement of rolls causes the strip to be flexed around a portion of the periphery of each roll. This re.- sults in better electrical contact of the strip with the upper roll and better frictional contact therewith to insure rotation of the roll when it is not driven. The pans 2S and 21 may be progressively stepped up, in the direction of strip travel, instead of down, as shown. In that case the electrolyte will flow in a direction opposite that of strip movement, instead of in the same direction, as in the arrangement illustrated.

Although I have illustrated and described but a preferred embodiment and practice of the invention, it will be recognized that changes in the arrangement and procedure disclosed may be made without departing from the spirit of the invention or the scope of the appended claims. Obviously, the invention may be used for the coating of strip composed of metal other than I claim:

1. Apparatus for progressively electroplating a continuously moving strip, comprising a plurality of pans across which the strip is passed successively in contact with electrolyte in the pans, said pans being spaced from each other horizontally and disposed side by side at progressively different elevations, each pan being adapted to contain electrolyte and having therein an electroplating anode, means for connecting the anode to a source of electroplating current, conduits directly connecting each pair of adjacent pans whereby electrolyte flows by gravity from one pan to the adjacent next lower pan, and strip guiding means in the spaces between adjacent pans for deflecting the strip downwardly as it passes from one pan to the next, said strip guiding means maintaining the strip horizontal in its passage through said pans and at a predetermined distance from the anode in each pan.

2. Apparatus for progressively electroplating a continuously moving strip, comprising a plurality of pans across which the strip is passed successively in contact with electrolyte in the pans, said pans being spaced from each other horizontally and disposed side by side at progressively difierent elevations, each pan being adapted to contain electrolyte and having therein an electroplating anode, means for connecting the anode to a source of electroplating current, conduits directly connectin each pair of adjacent pans whereby electrolyte flows by gravity from one pan to the adjacent next lower pan, and strip guiding means in the spaces between adjacent pans for deflecting the strip downwardly as it passes from one pan to the next in an amount substantially equal to the difference between the elevations of adjacent pans, said strip guiding means maintaining the strip horizontal in its passage through said pans and at a predetermined distance from the anode in each pan.

3. Apparatus for progressively electroplating a continuously moving strip, comprising a plurality of pans across which the strip i passed successively in contact with electrolyte in the pans, said pans being spaced from each other horizontally and disposed side by side at progressively different elevations, each pan being adapted to contain electrolyte and having therein an electroplating anode, means for connecting the anode to a source of electroplating current, conduits directly connecting each pair of adjacent pans whereby electrolyte flows by gravity from one pan to the adjacent next lower pan, and a pair of cooperating guide rolls having their axes displaced from each other horizontally in the spaces between adjacent pans for deflecting the strip downwardly as it passes from one pan to the next said guide rolls maintaining the strip horizontal in its passage through said pans and at a predetermined distance from the anode in each pan.

4. Apparatus for progressively electroplating a continuously moving strip, comprising a. plurality of pans across which the strip is passed successively in contact with electrolyte in the pans, said pans being spaced from each other horizontally and disposed side by side at progressively difierent elevations, each pan being adapted to contain electrolyte and having therein an electroplating anode, means for connecting the anode to a source of electroplating current, conduits directly connecting each pair of adjacent pans whereby electrolyte flows by gravity from one pan to the adjacent next lower pan, and a pair of cooperating guide rolls having their axes displaced from each other horizontally in the spaces between adjacent pans for deflecting the strip downwardly as it passes from one pan to the next in an amount substantially equal to the difference between the elevations of adjacent pans, said guide rolls maintaining the strip horizontal in its passage through said pans and at a predetermined distance from the anode in each pan.

5. Apparatus for continuously and progressively electroplating a moving strip, comprising a plurality of pans disposed side by side at progressively different elevations presenting electroplating cells, each being adapted to contain electrolyte and having therein an electroplating anode, means for connecting the anode to a source of electroplating current, across each of which the strip moves from end to end in a horizontal path in contact with the body of electrolyte therein and at a predetermined distance from the anode in the cell, the paths across the cells being disposed at progressively different elevations corresponding to the elevations of the pans and being positioned to maintain the strip in substantially the same relation to the anode in all of the cells; strip guiding means positioned outside of and adjacent the ends of each pan in position to maintain the moving strip in the path across the cell; and conduit means directly connecting each two adjacent pans whereby electrolyte flows through the conduit from the higher pan. to the lower pan of the adjacent pans.

6. In a method of electroplating strip, the steps including passing the strip successively in horizontal paths in contact with a plurality of spaced baths of electrolyte disposed side by side :at progressively different elevations while maintaining said horizontal paths at substantially the same vertical distance from anodes located in the baths, and flowing electrolyte by gravity directly from each bath to the next adjacent lower bath while effecting electrodeposition on to the strip from the electrolyte in each bath.

CLARENCE J. KLEIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 594,611 Emmens Nov. 30, 1897 991,685 Aldrich May 9, 1911 1,271,633 Walker July :9, 1918 1,544,506 Tytus Apr. 4, 1925 1,917,567 MacChesney July 11, 1933 2,093,238 Domm Sept. 14, 1937 2,314,369 Reed Mar. 23, 1943 

1. APPARATUS FOR PROGRESSIVELY ELECTROPLATING A CONTINUOUSLY MOVING STRIP, COMPRISING A PLURALITY OF PANS ACROSS WHICH THE STRIP IS PASSED SUCCESSIVELY IN CONTACT WITH ELECTROLYTE IN THE PANS, SAID PANS BEING SPACED FROM EACH OTHER HORIZONTALLY AND DISPOSED SIDE BY SIDE AT PROGRESSIVELY DIFFERENT ELEVATIONS, EACH PAN BEING ADAPTED TO CONTAIN ELECTROLYTE AND HAVING THEREIN AN ELECTROPLATING ANODE, MEANS FOR CONNECTING THE ANODE TO A SOURCE OF ELECTROPLATING CURRENT, CONDUITS DIRECTLY CONNECTING EACH PAIR OF ADJACENT PANS WHEREBY ELECTROLYTE FLOWS BY GRAVITY FROM ONE PAN TO THE ADJACENT NEXT LOWER PAN, AND STRIP GUIDING MEANS IN THE SPACES BETWEEN ADJACENT PANS FOR DEFLECTING THE STRIP DOWNWARDLY AS IT PASSES FROM ONE PAN TO THE NEXT, SAID STRIP GUIDING MEANS MAINTAINING THE STRIP HORIZONTAL IN ITS PASSAGE THROUGH SAID PANS AND AT A PREDETERMINED DISTANCE FROM THE ANODE IN EACH PAN. 